1. Technical Field
The present invention relates to a valve device for opening and closing valves incorporated in a connected part co which a liquid containing member such as an ink cartridge is connected, and to a liquid supply apparatus and a liquid ejection apparatus using the valve device.
2. Related Art
An inkjet recording apparatus is widely known as one type of liquid ejection apparatus. An ink cartridge, functioning as a liquid containing member, is set in the inkjet recording apparatus. In the inkjet recording apparatus, the ink cartridge supplies ink, functioning as a liquid, to a recording head, functioning as a liquid ejector.
An inkjet recording apparatus may have an ink cartridge set on a carriage, which includes a recording head, or in a printer main body. A recording apparatus having an ink cartridge set on the carriage is referred to as an on-carriage recording apparatus. A recording apparatus having an ink cartridge set in the printer main body is referred to as an off-carriage recording apparatus. For example, an off-carriage recording apparatus includes a cartridge holder, which functions as a connected part, in a cartridge accommodation opening for accommodating a cartridge. The holder has supply needles projecting from a surface to which the ink cartridge is to be connected. The supply needles are inserted into ink supply holes of the ink cartridge so as to connect the ink cartridge to the cartridge holder.
Ink remaining in an ink passage formed in the cartridge holder may leak from the holes of the supply needles when the ink cartridge is disconnected. To prevent such ink leakage, valves are arranged on the ink passage in the cartridge holder.
JP-A-2005-53212 describes a valve device for opening and closing valves in cooperation with the attachment and detachment (connection and disconnection) of an ink cartridge. This valve device includes a valve mechanism and a valve lever operably connected to the valve mechanism. When the ink cartridge is disconnected, the valve lever is located at a position at which the urging force of a spring closes valves. When the ink cartridge is connected, the ink cartridge pushes and pivots the valve lever so as to open the valves. This valve device uses a swing-type valve mechanism. More specifically, the valve mechanism includes a swing member having magnets, the quantity of which is in accordance with the number of valves provided in correspondence with the ink colors. The valve mechanism moves its swing member in a direction parallel to a surface of a valve arrangement unit of the cartridge holder. The swing-type valve mechanism is also operable by the power of an electric motor. When ink supply is unnecessary, such as when printing is not being performed, the valves are closed. This prevents ink leakage in case the user removes the ink cartridge after activating the recording apparatus.
FIG. 1 shows a swing member 124 included in a typical swing-type valve mechanism. The swing member 124 has a plurality of magnets 123. As shown in the FIG. 1, the swing member 124 of the swing-type valve mechanism is pivoted in a direction parallel to the surface of a valve arrangement unit 121 in a cartridge holder (in the direction of the arrow in the drawing). A plurality of valves 120 are arranged in the surface of valve arrangement unit 121 (surface parallel to the plane of the drawing). The swing member 124 has the magnets 123 arranged at positions corresponding to valve members 122, which are made of, for example, steel, of the valves 120. The magnets 123 attract the valve members 122. As shown in FIG. 2, the plurality of (six for example) magnets 123 corresponding to the valves 120 are arranged on a back yoke 125, which is a single flat plate. The back yoke 125 is fixed to a holder 124a, which is arranged on a distal portion of the swing member 124, in a manner that the magnets 123 face the corresponding valves 120.
The swing member 124 pivots about an axis when its inclined surface is pressed by a lever, which is driven by the power of an electric motor. The swing member 124 pivots to open and close the valves 120. More specifically, when the swing member 124 is arranged at a valve closing position indicated by a double-dashed line in FIG. 1, the magnets 123 are separated from the valve members 122. In this state, the valve members 122 are not attracted to the magnets 123 and the valves 120 are closed. When the swing member 124 rotates to a valve opening position at which the magnets 123 face the valve members 122, the valve members 122 are attracted to the magnets 123 thereby opening the valves 120.
In the closed state of the valves 120, each magnet 123 may be positioned between two adjacent valve members 122. In this case, when the interval between the valve members 122 is narrow, each magnet 123 may attract the adjacent valve members 122. This limitation has made it difficult to further downsize the valve arrangement unit 121 in which the valves 120 are arranged.
Further, the magnets 123 are arranged on the back yoke 125, which is a single large flat-plate. Thus, the magnetic force produced by the magnets 123 is not concentrated at the front of the swing member 124 and is dispersed in the lateral direction of the swing member 124. The diffused magnetic force is neither strengthened when the magnets 123 are moved toward the valve members 122 nor weakened when the magnets 123 are moved away from the valve members 122. Thus, the magnets 123 must be moved by a large amount. This requirement has made it difficult to downsize the valve device. To move the magnets 123 by a large amount, the distance from the pivot axis must be increased by elongating an arm 124b of the swing member 124 or the range of the pivot angle (swing angle) of the swing member 124 must be increased. This requirement has made it difficult to downsize the valve device in its height direction or its lateral direction.